Method and apparatus for plasma treatment

Abstract

A mirror field which faces a surface of a specimen to be treated and which has its field axis parallel to the specimen surface is formed in an atmosphere in a reactive gas, and a plasma of the reactive gas is then generated by introducing microwave energy into a region where the mirror field is formed, the thus-formed plasma being confined by the mirror field. The specimen is then treated by activated neutral particles which are produced by the plasma to the surface of the specimen. Preferably, an electric field is formed in the direction along the field axis of the mirror field in a region where the plasma is generated.

What is claimed is: 
     
       1. A method for plasma treatment comprising the steps of: forming a mirror field which faces a surface of a specimen to be treated and which has its field axis parallel to said surface in an atmosphere of a reactive gas;   generating a plasma of said reactive gas by introducing a microwave energy into a region where said mirror field is formed, said plasma being confined in said mirror field; and   treating said specimen by supplying activated neutral particles which are produced by said plasma to said surface of said specimen.   
     
     
       2. A method according to claim 1, wherein said specimen is a semiconductor wafer. 
     
     
       3. A method according to claim 1, wherein said treatment of said specimen is etching. 
     
     
       4. A method according to claim 1, wherein said treatment is the formation of a thin film. 
     
     
       5. A method for plasma treatment according to claim 1, further comprising forming an electric field in the direction along the field axis of said mirror field in a region where said plasma is generated. 
     
     
       6. An apparatus for plasma treatment comprising: a treatment container;   gas supply means for supplying a reactive gas into said treatment container;   specimen holding means for holding a specimen in said treatment container;   field formation means for forming a mirror field which faces a surface of said specimen to be treated, said mirror field having its field axis disposed parallel to said surface of said specimen in said treatment container; and   plasma generation means for generating a plasma of said reactive gas by introducing microwave energy into said mirror field formed by said field formation means.   
     
     
       7. An apparatus according to claim 6, wherein said field formation means is disposed outside said treatment container. 
     
     
       8. An apparatus according to claim 6, wherein said field formation means is disposed inside said treatment container. 
     
     
       9. An apparatus according to claim 6, wherein said field formation means comprises a pair of electromagnetic coils. 
     
     
       10. An apparatus according to claim 6, wherein said field formation means comprises a pair of permanent magnets. 
     
     
       11. An apparatus according to claim 6, wherein said mirror field formed by said field formation means and said microwave energy introduced by said plasma generation means respectively have such a strength and a frequency at which electron cyclotron resonance occurs in said treatment container. 
     
     
       12. An apparatus according to claim 6, further comprising an electric field formation means for forming an electric field in the direction along said field axis of said mirror field formed by said field formation means in a region where said plasma is generated. 
     
     
       13. An apparatus according to claim 12, wherein said electric field formed by said electric field formation means is a high frequency electric field. 
     
     
       14. An apparatus according to claim 13, wherein said electric field forming means comprises a pair of electrodes disposed so as to sandwich said region where said plasma is formed, and a power source for applying a high-frequency voltage between said pair of electrodes. 
     
     
       15. An apparatus according to claim 14, wherein said pair of electrodes are disposed outside said treatment container. 
     
     
       16. An apparatus according to claim 14, wherein said pair of electrodes are disposed inside said treatment container.